There is never a decimal point in any of the coding systems.
The pin dot is needed because some of the magnetic field will come out of the coil. This will interact with other components, specifically other inductors, but the PCB and any box may have an effect as well.
A minor nitpick; the magnetic field comes out the top and bottom of the coil, the pin identifier is totally irrelevant under those conditions. However I think we agree the dot is there to ensure correct insertion.